出版社：Association of College and University Biology Educators
摘要：This paper describes a series of laboratory exercises for upper level biology courses, independent research and/or honors programs. Students sampled fish from a local water body with the assistance of a local fish and wildlife agency. Tissue samples from collected fish were utilized to obtain estimates of the stable isotopes 13C and 15N. An open-source mass balance model was utilized to estimate fish diets from isotope values. Isotopes were also used to measure trophic position (TP) and evaluate dietary niche overlap between native and introduced species. It was found that 15N concentrations increased with each trophic level starting with benthic algae (lowest) to omnivores, then primary carnivores and ultimately piscivores (highest). Estimates of 13C suggested all collected taxa utilized littoral habitats for feeding purposes. Native chain pickerel (Esox niger) had the highest 15N and TP estimates at 14.4 and 4.11, respectively. Nonnative largemouth bass (Micropterus salmoides) 15N and TP estimates were 13.56 and 3.86, respectively. Model estimates suggested that chain pickerel and largemouth bass diets were partitioned: pickerel consumed only fish and bass consumed principally invertebrates with some intermittent fish contributions. This lab helped integrate multiple disciplines, provide practical experience, and encourage criticalthinking skills while educating students about trophic ecology.
关键词：Stable isotopes;trophic position;dietary niche;nonnative species
